Fuel injection delivery valve with reverse flow venting

Abstract

Fuel delivery valving operatively mounted in an axially extending center bore of a high pressure pump rotor. The valve axially shifts between an open position in which a charge of fuel generated by the pump is transmitted as a pressure wave to a fuel injector nozzle and a closed position in which the pump charging chamber is sealed from the injection line and the injection line is vented to low pressure so that secondary pressure waves reflecting from the injector nozzle will be routed to the low pressure line for dissipation therein rather than rebounding from the delivery valve. This improves engine operation efficiency and eliminates seocndary injection of fuel by the injector nozzle and high hydrocarbon and smoke emissions. One embodiment has a fuel delivery valve operatively mounted in each discharge fitting of a hydraulic head assembly of the fuel injection pump.

We claim: 
     
       1. A fuel injection pump including high pressure pumping means and separate discharge fittings for supplying fuel from a source of liquified fuel to the combustion chambers of an internal combustion engine through fuel injector nozzles connected to fuel injection lines into which high pressure pulses of fuel are delivered from said high pressure pumping means through said fittings, the improvement comprising delivery valve assembly means operatively mounted in each of said fittings for feeding pulses of fuel into said fuel injector lines and for retracting fuel from said fuel injector lines, each of said delivery valve assembly means including a valve element operatively mounted for shifting movement in an associated fitting, an inlet passage in said fitting for receiving pulses of high pressure fuel from said high pressure pumping means, said delivery valve element having hydraulic passage means therein which hydraulically feeds said pulses to an associated high pressure line for delivery to its injector nozzle for subsequent feed into the associated combustion chamber, said valve assembly means having fluid passage means therein so that pressure waves of fuel reflecting from said fuel injector nozzle will be routed by said valve element to a low pressure area in said pump to eliminate secondary fuel injections. 
     
     
       2. A fuel injection pump including high pressure pumping means for supplying fuel from a fuel source to the combustion chambers of an internal combustion engine through fuel injector nozzles connected to fuel injection lines into which high pressure pulses of fuel are delivered from the high pressure pumping means, the improvement comprising a pump rotor having a bore therein, a valve element operatively mounted in said pump rotor bore, an inlet passage in said pump rotor for receiving the pulses of fuel from the pumping means, said valve element having first fluid passage means therein which, upon movement of said valve element from a first position to a second, shifted position, hydraulically transfers said pulses of fuel to a predetermined one of said fuel injection lines for delivery to its respective fuel injection nozzle, and having second fluid passage means therein which, upon movement of said valve element from said second position to said first position, hydraulically transfers pressure waves of fuel reflected from said predetermined injector nozzle to the fuel source. 
     
     
       3. A fuel injection pump including high pressure pumping means for supplying fuel from a fuel source to the combustion chambers of an internal combustion engine through fuel injector nozzles connected to fuel injection lines into which high pressure pulses of fuel are delivered from the high pressure pumping means, the improvement comprising a pump rotor having a bore therein, a valve element operatively mounted in said pump rotor bore, an inlet passage in said pump rotor for receiving the pulses of fuel from the pumping means, said valve element having a fluid passage means therein which, upon movement of said valve element from a first position to a second, shifted position, hydraulically transfers said pulses of fuel to a predetermined one of said fuel injection lines for delivery to its respective fuel injection nozzle, and said pump rotor having fluid venting passage means therein which, upon movement of said valve element from said second position to said first position, hydraulically transfers pressure waves of fuel reflected from said predetermined injector nozzle to the fuel source.